Defenders of California's traditional marriage amendment say they have new grounds to appeal a former judge's ruling which declared Proposition 8 to be an unconstitutional violation of gay Californians' civil rights.

Last year, U.S. District Judge Vaughn Walker ruled the state law defining marriage as being between a man and a woman was unconstitutional based on civil rights grounds. He also ordered the state to stop enforcing the measure.

But recently Walker disclosed that he's a homosexual in a 10-year relationship with another man.

Attorneys for Protect Marriage, the coalition that sponsored Proposition 8, are now arguing that Walker should have removed himself from the case because his impartiality could be questioned.

They are asking the judge who inherited the case when Walker retired at the end of February to toss out Walker's August 2010 decision.

"If at any time while this case was pending before him, Chief Judge Walker and his partner determined that they desired, or might desire, to marry, Chief Judge Walker plainly had an interest that could be substantially affected by the outcome of the proceeding," wrote attorneys for the coalition of religious and conservative groups that put Proposition 8 on the November 2008 ballot.

The 9th U.S. Circuit Court of Appeals is reviewing its legal merits at the request of the voter-approved measure's sponsors.

Walker has said that he did not consider his sexual orientation to be any more a reason for recusal than another judge's race or gender normally would be. A spokeswoman said Monday that the judge wouldn't comment on the motion.

The lawyers for Protect Marriage said they had purposely refrained from raising the judge's sexual orientation as a legal issue until Monday.

"We deeply regret the necessity of this motion. But if the courts are to require others to follow the law, the courts themselves must do so as well," Protect Marriage General Counsel Andy Pugno said.